Fertilizer use and soil biological health and assessment of its indices

Abstract

Variations in soil properties and environmental factors, such as temperature, water availability, aeration and nutrient supply, have a large effect on the population dynamics of soil microorganisms so that care must be taken to standardise sampling procedures as much as possible. The primary aims of soil quality monitoring, however, are: to establish benchmark values (or ranges) for key indicators; and to monitor changes over time. The availability and standardisation of methods for the measurement of biological indicators and its threshold values by soil laboratories is a challenge. While the absolute values of many biological indicators are of little value without the benchmarks, the change in indicator values, either over time or compared to a nearby reference site, can measure changes in soil quality, provided that the indicators are relevant to critical soil functions.